Approach

To

Orthopedic

Oncology

OUTLINE

Introduction

Classification of Bone tumors

Clinical Presentation

Staging of Bone tumors

Primary Bone tumors

Case Presentation

A bone tumor is an abnormal growth of

cells within a bone.

The definate cause of bone tumors is

unknown.

Possible causes include:

1.Genetic defects passed down

through families

2.Radiation

3.Injury

They often occur in areas of rapid bone

growth.

Medline plus: Service of U.S national Library of Medicine

http://www.nlm.nih.gov/medlineplus/ency/article/001230.htm

Cancers that start in the bones are

referred to as primary bone tumors.

Cancers that start in another part of the

body (such as the breast, lungs, or colon)

are called secondary or metastatic bone

tumors.

Medline plus: Service of U.S national Library of Medicine

http://www.nlm.nih.gov/medlineplus/ency/article/001230.htm

Classification of Bone tumors

Most classifications of bone tumors are

based on the dominant tissue in the

various lesions.

Classification of Bone tumors

Clinical presentation

History

Examination

Imaging

Biopsy

Important differential diagnosis

History

History is often prolonged, results in delay

of treatment.

Patients most of the time will be

completely asymptomatic until the

abnormality is discovered on X-ray.

This is more of benign lesions, common in

children and rare after 30

Malignant tumors can be silent if they are

slow growing and there is room for

expansion like cavity of the pelvis.

AGE

A Useful clue.

Many benign tumors present during

childhood and adolescence

Chondrosarcoma and fibrosarcoma

typically occur in 4th and 6th decades

adults.

Myeloma rarely seen before 6th decade.

Patients over 70 years metastatic bone

lesions are more common than primary

tumors.

PAIN common complaint and gives little

indication of the nature of lesion.

Progressive and unremitting pain is a very

important symptom though.

It may be caused by:

1. Rapid expansion

2. Central hemorrhage or degeneration of

the tumor

3. Pathological fracture.

Pathological fracture

may be the first and only clinical sign.

In elderly people whose bones usually

fracture at the cortico-cancellous

junctions, if they get mid shaft fracture

it is regarded as pathological until

proven otherwise.

Other presentations

Swelling:

Appearance of a lump, may be alarming.

Neurological symptoms:

Parasthesia and numbness may be caused

by pressure or stretching of a peripheral

nerve.

Progressive dysfunction is alarming and

suggests invasion by an aggressive tumor.

Examination

If there is a lump: Where does it arise?

Is it well defined or not?

Soft, hard or pulsatile?

Tender?

Swelling can be diffuse and the overlying

skin warm and inflamed which makes it

hard to distinguish from infection and

hematoma.

If it is near a joint:

is there any movement limitation?

Spinal lesions cause muscle spasm, back

stiffness or painful scoliosis.

Examination will focus on symptomatic part

but it should include :

lymph nodes

pelvis

abdomen

chest and spine.

Imaging

X-ray:

it’s not useless imaging technique..

There might be obvious abnormality of the

bone:

1. Cortical thickening

2. Discrete lump

3. Cyst

4. Ill-defined destruction

Is it in the metaphysis or diaphysis?

Is it solitary or multiple lesions?

Margins are well or ill defined?

Note: cystic lesions are not necessarily

hollow cavities: any radiolucent material

may look like a cyst (e.g fibroma and

chondroma)

If the boundaries of the cyst is well defined is

mostly benign.

If it is hazy and diffuse it is mostly invasive tumor.

Bone surfaces: periosteal new bone formation

and extension of the tumor to the soft tissues

are suggestive of a malignant tumor.

Soft tissues:

are the muscle planes distorted by the

swelling?

Is there any calcification?

X-ray is not a definitive diagnosis and further

investigation must be done to confirm.

Other techniques of imaging used are :

Radionuclide scanning

CT

MRI

They all help in viewing the lesions better, view

soft tissue and detect skip lesions too.

Patient must not go for biopsy if MRI or CT is

planned for him as it will distort the image and

appearances.

Biopsy

There are three ways:

1.Needle biopsy:

Must be performed by experienced personal.

2. Open biopsy:

most reliable way of obtaining a representative

sample.

3. Excisional biopsy: for benign tumors.

Deferential Diagnosis

Staging of bone tumors

Staging is the process of finding out how

far the cancer may have spread.

This is very important because the type of

treatment and the outlook for recovery

(prognosis) depend on the stage of the

cancer.

In treating tumors we are facing two conflicting

principles:

1. Lesion must be removed widely to ensure it

doesn’t recur.

2. Damage must be kept minimal.

The balance between the 2 conflicting objectives

depends on knowing:

1. How the tumor behaves (Aggressiveness)

2. How far it has spread.

The answers to these two questions are embodied in

the staging system of Enneking.

Tumor

Benign

Latent Active Aggressive

Malignant

Low GradeHigh

Grade

Aggressiveness

Enneking Staging systemBenign Tumors

Latent Well defined margin. Grows slowly and then stops.

Remains static/heals spontaneously E.g Osteoid

osteoma

Active Progressive growth limited by natural barriers.

Not self limiting. Tendency to recur E.g Aneurysmal

Bone cyst

Aggressive Growth not limited by natural Barriers E.g Gaint cell

tumor

Malignant Tumors

Low Grade Moderately aggressive and takes a long time to

metastasize

High Grade Very aggressive and metastasize early

Spread

Assuming that there is no metastases, the

local extent of the tumor is the most

important factor in deciding how much

tissue to be removed.

Spread

Intra-compartmental

Extra-compartmental

Spread

Lesions that are confined to an enclosed

space (e.g Bone cavity, joint cavity or

muscle group within its fascial envelope)

are called Intra-compartmental.

Lesions that extend into inter-fascial or

extra-fascial with no natural barrier to

proximal or distal spread are called Extra-

compartmental. (E.g pelvis, axilla)

Surgical stage

Staging the tumor is an important step towards

selecting the best operation suited to the

patient.

Bone sarcomas are divided as follows:

1. Stage 1: All low grade sarcomas

2. Stage 2: Histologically high grade lesions

3. Stage 3: Sarcomas which have metastasized.

Surgical stages described by Enneking

Stage Grade Site Metastases

IA Low Intracompartmental No

IB Low Extracompartmental No

IIA High Intracompartmental No

IIB High Extracompartmental No

IIIA Low Yes

IIIB High Yes

Management

Primary bone tumors

Divided into Benign and Malignant.

They are rare to occur and secondary

bone tumors are more common.

Osteoid Osteoma

Giant cell Tumor

Enchondroma

Benign Tumors

Osteoid Osteoma

peak incidence in 2nd and 3rd decades,

M:F = 3:1

small, round radiolucent nidus (<1 cm) surrounded

by dense bone

tibia and femur most common

produces severe intermittent pain, mostly at night

characteristically relieved by NSAIDs

Osteoid Osteoma

Osteochondroma

2nd and 3rd decades, M:F = 1.8:1

metaphysis of long bone

cartilage-capped bony spur on surface of bone

may be multiple

higher risk of malignant change

generally asymptomatic unless impinging on

neurovascular structure

malignant degeneration occurs in 1-2%

Enchondroma

2nd and 3rd decades

50% occur in the small tubular bones of the hand

and foot; others in femur, humerus, ribs

benign cartilaginous growth, develops in

medullary cavity

single/multiple enlarged rarefied areas in tubular

bones

lytic lesion with sharp margination and central

calcification

malignant degeneration occurs in 1-2%

Enchondroma

Cystic lesions Include

unicameral/solitary bone cyst (most common),

fibrous cortical defect

children and young adults

local pain, pathological fracture or incidental

detection

lytic translucent area on metaphyseal side of

growth plate

cortex thinned/expanded; well defined lesion

treatment of unicameral bone cyst with steroid

injections ± bone graft

treatment only necessary if symptomatic

osteochondroma: resection

cystic lesions: curettage and bone graft

Cystic lesions

Giant cell Tumor

affects patients of skeletal maturity, peak 3rd decade

distal femur, proximal tibia, distal radius, sacrum, tarsal bones, spinal (osteoblastoma)

cortex appears thinned, expanded; well-demarcated sclerotic margin

local tenderness and swelling

aggressively destroy bone

15% recur within 2 years of surgery

giant cell tumour occasionally metastasizes (1-2%)

Treatment

intralesional curettage + bone graft or cement

wide local excision of expendable bones

Giant cell tumor

Malignant tumors

Multiple myeloma

Osteosarcoma

Ewing’s sarcoma

Chondrosarcoma

Osteosarcoma mostly frequently diagnosed in 2nd decade of life (60%)

Mostly affects distal femur (45%), proximal tibia (20%)

and proximal humerus (15%)

invasive, variable histology; frequent metastases without

treatment

painful, poorly defined swelling

x-ray shows

characteristic periosteal elevation and spicule formation

representing tumour extension into periosteum

treatment: complete resection (limb salvage, rarely

amputation), chemotherapy

survival “ 70%

Osteosarcoma

Chondrosarcoma

primary

previous normal bone, patient over 40; expands into

cortex to give pain, pathological fracture, flecks of

calcification

secondary

malignant degeneration of pre-existing cartilage

tumour such as enchondroma or osteochondroma

most commonly occurs in pelvis, femur, ribs,

scapula, humerus

unresponsive to chemotherapy, treat with

aggressive surgical resection + reconstruction

Chondrosarcoma

Ewing’s sarcoma

most occur between 5-20 years old

florid periosteal reaction in diaphysis of long bone

moth-eaten appearance with periosteal lamellated

pattern (onion-skinning)

present with mild fever, anemia, leukocytosis

and increased ESR

metastases frequent without treatment

treatment “ resection, chemotherapy, radiation

survival “ 70%

Multiple myeloma most common primary malignant tumour of bone

in adults

90% occur in people >40 years old

present with anemia, anorexia, renal failure,

nephritis, increased ESR, bone pain, compression

fractures, hypercalcemia

diagnosis

punched-out lytic lesions on x-ray at multiple bony

sites

serum/urine protein electrophoresis

treatment: chemotherapy, radiation, surgery for

symptomatic lesions or impending fractures

References Medline plus: Service of U.S national Library of

Medicine http://www.nlm.nih.gov/medlineplus/ency/article/001230.htm

Apley’s system of orthopedics and fractures (Ninth Edition)

Apley’s Concise system of orthopedics and fractures (Third Edition)

American Cancer society http://www.cancer.org/Cancer/BoneCancer/OverviewGuide/bone-cancer-overview-staging

First Aid for the USMLE Step 1 2011

Toronto notes 2009